Has anyone ever added down to a Burrow after the fact?

I just noticed one of my quilts has a single baffle that is basically empty. I checked to see if it was "sharing" with an adjacent baffle by trying to push down from those, but that is not that case. I certainly didn't leak an entire baffle so I assume it was just an oversight during production.

I'm OK with sewing, but since this is the baffle where the footbox starts/triangle piece, it's not as simple.